A 22-year-old woman has sought medical care for a protrusion on her left foot that has now been described as a fully-formed third nipple.
Appearing in a report published in scientific journal Dermatology Online, researchers believe the case may be the first of its kind.
Photographs accompanying the report show the 4cm nipple in the plantar region of the patient’s left foot.
The report also says the nipple is surrounded by areola and hair.
"She had no complaints of pain, pruritus, or alterations in volume or colour," the report said.
"During her pregnancy or post-partum period, there had been no change in the lesion.
"Family history for similar conditions was negative.
"To our knowledge, this is the first report of supernumerary breast tissue on the foot".
Up to 5 per cent of people are thought to suffer from the condition although most extra nipples tend to be located above the waist.